A route to the fabrication of electronic devices is provided, in which the devices consist of two crossed wires sandwiching an electrically addressable molecular species. The approach is extremely simple and inexpensive to implement, and scales from wire dimensions of several micrometers down to nanometer-scale dimensions. The electronic devices can be used to produce crossbar switch arrays, logic devices, memory devices, and communication and signal routing devices. The construction of molecular electronic devices is achieved on a length scale than can range from micrometers to nanometers via a straightforward and inexpensive chemical assembly procedure. The molecular switchable devices in the cross-bar geometry are configurable while the conformational change is controlled by intramolecular forces that are stronger than hydrogen bonding. The method of the present invention is directed to configuring an ensemble of molecular switches in a prescribed manner in cross-bar geometry and then making such configuration either substantially permanent or stable with respect to temperature fluctuations.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A method of configuring an ensemble of molecular switches in a prescribed manner in crossbar geometry and then making such configuration either substantially permanent or stable with regard to temperature fluctuations, comprising the steps of: (a) providing said ensemble of molecular switches in said crossbar geometry, each said molecular switch comprising a pair of crossed wires that form a junction where one wire crosses another at an angle other than zero degrees; (b) providing said junction with at least one connector species connecting said pair of crossed wires in said junction, said junction having a functional dimension in a range from nanometers to micrometers, wherein said at least one connector species and said pair of crossed wires forms an electrochemical cell, said connector species comprising a molecule having at least one active dipole; and (c) either substantially permanently configuring said connector species where said connector species has one active dipole or stably configuring said connector species where said connector species has more than one active dipole.
2. The method of claim 1 wherein said configuration is made substantially permanent by forming a single bond within said connector species that is at least three times stronger than a hydrogen bond.
3. The method of claim 2 wherein said connector species is substantially permanently configured by the following steps: (a) forming said connector species in said junction; (b) applying an external electric field to said junction to configure said connector species; (c) replacing a hydrogen atom with a species that forms a bond with a portion of said dipole that is stronger than said hydrogen bond; and (d) removing said electric field, leaving said switch substantially permanently in said configuration.
4. The method of claim 3 wherein said hydrogen atom is replaced by a member selected from the group consisting of fluorine, chlorine, NH 2 , divalent metal, and sulfur.
5. The method of claim 4 wherein said connector species remains switchable by employing associative bonds selected from the group consisting of F N, Cl, N, NH 2 . . . N, and (Met) . . . N, where (Met) is said divalent metal, said connector species being switchable upon exposure to an electric field having a strength greater than said hydrogen bond.
6. The method of claim 4 wherein said connector species is made permanently configured by forming a covalent bond between said sulfur and oxygen.
7. The method of claim 2 wherein said connector species has a formula given by where the letters in formula (I) mean any of the following: A CH; N; C-alkyl; C-halogen; C-OH; C-OR(ether); C-SR(thioether); C-amide; C-ester or thioester; B CH; N; C-alkyl; C-halogen; C-OH; C-OR(ether); C-SR(thioether); C-amide; C-ester or thioester; C CH; N; C-alkyl; C-halogen; C-OH; C-OR(ether); C-SR(thioether); C-amide; C-ester or thioester; D CH; N; C-alkyl; C-halogen; C-OH; C-OR(ether); C-SR(thioether); C-amide; C-ester or thioester; E CH; N; C-alkyl; C-halogen; C-OH; C-OR(ether); C-SR(thioether); C-amide; C-ester or thioester; F CH; N; C-alkyl; C-halogen; C-OH; C-OR(ether); C-SR(thioether); C-amide; C-ester or thioester; G CH; N; C-alkyl; C-halogen; C-OH; C-OR(ether); C-SR(thioether); C-amide; C-ester or thioester; J CH; N; C-alkyl; C-halogen; C-OH; C-OR(ether); C-SR(thioether); C-amide; C-ester or thioester; M CH 2 ; CF 2 ; CCl 2 ; CHOCH 3 ; CHOH; CHF; CO; CH CH; CH 2 CH 2 ; S; O; NH; NR; NCOR; NCOAr; Q CH; nitrogen; phosphorus; boron; and Y O; S.
8. The method of claim 1 wherein said configuration is made stable by forming a plurality of hydrogen bonds within said connector species.
9. The method of claim 8 wherein said connector species is stabilized in one of two stable states by the following steps: (a) providing said plurality of dipole groups on said connector species, each capable of hydrogen bonding with an adjacent dipole group on said connector species; (b) forming said connector species in said junction; (c) applying an external electric field to said junction to configure said connector species; and (d) removing said electric field, leaving said switch in said stabilized configuration.
10. The method of claim 9 wherein said dipole groups comprise urea or amide functional groups.
11. The method of claim 10 wherein said dipole groups employ N H . . . F bonds to increase hydrogen bonding energy.
12. The method of claim 8 wherein said connector species has a formula given by where the letters in formula (II) mean any of the following: A CH; N; C-alkyl; C-halogen; C-OH; C-OR(ether); C-SR(thioether); C-amide; C-ester or thioester; B CH; N; C-alkyl; C-halogen;; C-OH; C-OR(ether); C-SR(thioether); C-amide; C-ester or thioester; C CH; N; C-alkyl; C-halogen; C-OH; C-OR(ether); C-SR(thioether); C-amide; C-ester or thioester; D CH; N; C-alkyl; C-halogen; C-OH; C-OR(ether); C-SR(thioether); C-amide; C-ester or thioester; E CH; N; C-alkyl; C-halogen; C-OH; C-OR(ether); C-SR(thioether); C-amide; C-ester or thioester; F CH; N; C-alkyl; C-halogen; C-OH; C-OR(ether); C-SR(thioether); C-amide; C-ester or thioester; G CH; N; C-alkyl; C-halogen; C-OH; C-OR(ether); C-SR(thioether); C-amide; C-ester or thioester; J CH; N; C-alkyl; C-halogen; C-OH; C-OR(ether); C-SR(thioether); C-amide; C-ester or thioester; M CH 2 ; CF 2 ; CCl 2 ; CHOCH 3 ; CHOH; CHF; CO; CH CH; CH 2 CH 2 ; S; O; NH; NR; NCOR; NCOAr; Q CH; nitrogen; phophorus; boron; and Y O; S.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
December 14, 2000
December 16, 2003
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